kVA to kW Calculator

If you have ever sized a generator, a transformer, a UPS or a switchboard, you will have run into the difference between kVA and kW, and the power factor that links them. This calculator makes the conversion instant and clear. Apparent power, measured in kVA, is the total power flowing in an alternating current circuit. Real power, measured in kW, is the portion that actually does useful work, turning a motor, heating an element or lighting a room. The two are not the same whenever the load is inductive, such as motors, pumps, compressors and fluorescent lighting, because those loads draw extra current that flows back and forth without doing work. The power factor, a number between 0 and 1, captures how much of the apparent power is real, and the relationship is simply kW equals kVA times power factor. Enter a kVA rating and a power factor and the calculator returns the real power in kW, the reactive power in kVAR (the non-working part), and confirms the apparent power, all updating as you type. This matters in practice because equipment is often rated in kVA while your actual working load is in kW, so getting the conversion right stops you from undersizing a generator or transformer, or paying for capacity you cannot use. It is equally handy for electricians, engineers, facilities managers and anyone planning a power installation or hiring a genset for an event or site. Because reactive power is shown too, you can also see how poor power factor inflates the kVA you need, which is the whole reason power factor correction exists. The formulas and a worked example are explained below.

Calculate.co.nz is proud to be partnered with Health Based Building, a leader in sustainable and health-conscious building innovation. With over a century of experience, they develop high-performance systems like Foreverbreathe Specification, Magnum Board, and Foreverbreathe Paints to support energy-efficient, non-toxic living environments. Their commitment to healthier homes aligns with our belief that informed choices lead to better outcomes for Kiwi households.